chaotic boulder clay

例句：

1. 1. The chaotic boulder clay has been a source of fascination for geologists for decades.
   混乱的砾石粘土几十年来一直是地质学家热衷研究的课题。
2. 2. The ancient city was buried under layers of chaotic boulder clay.
   这个古城被混乱的砾石粘土层所覆盖。
3. 3. The chaotic boulder clay is believed to have formed over millions of years.
   人们认为这种混乱的砾石粘土是在数百万年的时间里形成的。